Can we just have struct inheritence already?

[Era Scarecrow]

On Sunday, 9 June 2019 at 08:05:34 UTC, Manu wrote:
> Imagine if we could just write:
>
> struct DerivedStruct : BaseStruct
> {
>     // derived members
>     //...
> }
>
> Just imagine!

Mhmm...

  I'd think struct inheritance would follow the original C++'s 
ideology.

  So probably:

  1) No Virtual functions. All functions are FINAL (replacing)
  2) No polymorphism.
  3) Limited casting (Casting up/back is easier than casting down, 
with space limitations in mind), though casting could simply be 
disallowed but that seems unlikely when you get low level.

  In such a case you could build a base struct and then add onto 
it for several structs behaviors. Being able to avoid using the 
GC as much as possible that would help. Also most of the 
functions/structures are basically copy/pasted with overriding 
functions completely replacing the previous ones.

  I've been wanting this for a while. I had a prototype set of 
templates to do this very thing! But... it no longer works, 
hasn't since... oh i don't remember. I'd have to pull the old 
files out...

  I'd probably ask a debugging feature where you could output the 
new finalized struct in it's full source code or maybe rather 
just it's API specifying what functions/variables come from 
where, so you get a clear picture of what you're working with if 
you inherit several times/deep.